Matrix-retainer.



ft t) fit JAMES W. IVORY, OF I'I-IILAIDELPHIA,v PENNSYLVANIA.

MATRILRETAINER.

Specification of Letters Patent.

Application tiled September' 15, 1908. Serial No. 453,101. i'

To all whom it may concern:

lle it known that' l, .titans lV. lvonv. a siiliject ot the King ot'x (treat Britain, residing' in the eitY and (-ouiity of Philadelphia, State ot Pennsylvania. have invented a new and useful Matrix-lietainer, of whieh the following` irl: a speritieatioii.

The purpose ot iii'v invention is to retain a dental niatrix to a tooth liv a retainer hav-v ing;` a detiiiitelimiting' at'tion upon the points ot' the retainer.

The t'urther purpose ot niv invention is to retain a dental uiatrix in ifon'torniit)Y with the surt'aee ot the tooth.

A\ tui-thor purpose ot inv invention is to draw the surtaiis. ot' the dental matrix lose :iliout the hott)Y otl the tooth4 it tui-ther purpoa` ol' niv invention is to press the dental inatrix inwardljY at' it',` outer surt'at-e.

li t'urther wonsists ot other novel tmitnres it t'oiistrui-tioii. as limiting the distaiif'e of where the points engage the hand liv tlie length ot the extending jaws as it hears upon the Acrown ot the tooth. as will he hereinafter t'ullv set' forth.

For thil purpose ot illustratinILr in v invention. l have shown in the aitoiiipan vinggl drawings several illustrations otE applicationsl tlioroot whitli are at present preferred h v uw. sinte the saine have heen t'ound iii practiie to give satisfactory and reliable resultS. although it is to he understood thatr the various instruuientalitiee of which in v iiivoiition consists can he variouslyy arranged and organized and that niv invention is not liniittd to the precise arrangement and organization of these instrumentalities as l ereii shown and dost-ritual.

Figure l represents a striuturo enihodvuit; in) invention iii perspettive. Fig. Q represents the struet'ure ot Fig. l in top plan view. lig. Il represents the strueture shown in hie'. 2 iii transverse seetion along line .r ma; theta-ot". looking' iii the diret'tiou ot the arrows. Figs. l and 5 i'ept'went in perspet-tivo applications ol niv invention to other i'oi'iiis ot vlanipA tiiniilar numerals ol' i'et'ereiu-e vorrosponiling parts iii the tie'urts.

lleterrinzgi to tht` drawings: in hin'. l l t..i\t applied iiiy invention to the general torni ot wlaiiip illustrated in in v Patent No. ttti'lit ot' .\pril t. tHttt. and t'or thatV piu'- indient@ in arms 2, 2 and attaching points S, 3. The center of the how is apertured at et to permit. passage ot a rod 5 threaded at 6 and controlled hy a thnmh nut 7. The rod 5 is pivoted at 8 to links 9 whichl are connected at l and ll to ears 12, i3 upon any Suit-- able part of the arms, the :structure being arranged in such manner that movement; of the rod in one direction will draw the terniinal points 3, 3 toward each other, While iiiovenient in the opposite direction will perniit the bow to segarate them.

rl`he matrix oand t4 is preferably provided with apertures with whieh the points" 3, 3 engage and the niatrix is thus drawn about tl e tooth by these points. Ditloulty has heen niet with, however, in the fact that the tension upon the band is exertedfat a. Single point only upon each side and that; point pref-- eraely near the edge ot' the band closest to the root of the tooth with the renlt that there has been a tendency, ften marked, to` bulge or flare the edge of the band nearest: to the crown of the tooth with-resultant failure to properly contour to the shape of the tooth, esides a tendency for the points 3, 3 of the retainer to slip down on the neck of the tooth. l'n in)Y invention I overeonie this olojeetion by providingr transversely directed jaws or clainps 15 preferably curved in forni as at itt and so positioned as to exert an inward pressure upon the surface of the niatrix band between the point at which the tension applied and the edge toward the crown ot' the tooth, the enrved portion preferably ove-rtappiiify the crown thus holding the points 3 at a relative distance from the (-rown, and heilig' iiiade longer or shorter to contorni to length ot the tooth oi' contour of the saine. M v invention is in lio way re stritted to the exact location or shape of the supplemental jaws l5 illustrated herein. l extend the supplemental jaws l5 Slightly lielow the points or jaws 3. .il as at l5 in line with jaws l5 assisting' to torni the matrix to the rui-ve otthe tooth and limiting the depth ol engagement ot the points or jaws 3, 3 with the matrix.

ln Fig'. tl have applied iiiy invention to a elanip ot' the type shown in patent. to Minoli No. Tait-'38 of .luiitt3, .1905, owned by me, in ywhiih the jaws l? are pivot'ed but not; erosseit to provide extensions 1S within whi li the nut. lit operates as a wedge Screwt-f o ninthA usey ot a, spriii.;- how 't toriiiinatiiig I ine` upon tho thread 2t) and foreingrt'ho jaws 17 'together against s ring 21 or permitting the to be separated y said spring. I have chsentoillustrate the same form of suppleniental jaws 15 in connection with the `5 terminal points 3 as in Figs. 1, 2 and 3. In Fig. 5 I'have shown my invention as applied to a form of clamp comprising a ,simple spring adapted to be separated by special pliers when being applied to the matrx. In this illustration the spring band 22 terminates -in points 3 beside which supplemental jaws 15 are placed.

Having thus described my invention, what I claim as new and desire to secure by *LetI ters Patent, is: ,e

In a matrix clamp, arms, means for moving them toward and from each other, terminals upon said arms to bring tension upon the matrix, and supplemental jaws extending transversely to the plane of movement of thejaWs and adapted to press against the matrix. A,

- JAMES W. IVORY.

Witnesses:

' W. S. JAoKsoN,

JOHN A. WIEDERSHEIM. 

